The magician hypnotises the audience with his pocket watch to make them follow his commands.

hypnotises 是动词 hypnotise 的第三人称单数形式。hypnotise 由词根 hypno-（来自希腊语，表示"睡眠"）和动词后缀 -tise（表示"使...化"）组成，字面意思是"使进入睡眠状态"，引申为"催眠"的意思。